The Cell Engineering core accelerates progress in ADPKD research by providing new cell models that have been long missing from the field. In the last funding period, the core developed novel inducible PKD1/2 knockout cells. Our research community has extensively used these models to move their programs of investigation forward. Here, we will build on our successes to develop new models and expand services to further expedite ADPKD research. Five aims are proposed: Aim 1: The core will continue to distribute high- quality, well-characterized primary cells and immortalized cell lines from inducible murine models of ADPKD. Tetracycline inducible Pkd1/2 KO kidney epithelial cells that provide a red-to-green switch to report Cre- mediated KO are a highlight. Aim 2: The core will offer genetically characterized cells from Human Kidney Cysts, with the goal of creating immortalized human cystic cell lines. A human ADPKD cyst biobank will also be formed in close collaboration with Clinical CORE E, providing an unprecedented opportunity to examine genotype-phenotype relationships. Aim 3 A novel 3-D kidney organoid culture system, derived from the renal epithelial cells of ADPKD mice (Animal Core, CORE C), is available to elucidate mechanisms of cystogenesis, and screen therapeutic agents. These organoids have inducible genetic recombination, allowing heterogeneous inactivation of the polycystins, similar to what occurs in the human disease. The system should provide an in vitro organ model where ?wild type? cells make tubes and ?mutant? cells reliably make cysts. Aim 4 CRISPR technology will be employed to create renal epithelial cells harboring specific ADPKD mutations in PKD1 or PKD2. Custom cell engineering is available upon request. Aim 5 The core will offer a Training Workshop in ADPKD Cell Culture Methods, consisting of didactic and hands-on training activities in the theory and practice of cell culture techniques for ADPKD research. We anticipate a high demand for our cells and services. They should accelerate progress and advance ADPKD science.